In an internal combustion engine, an electromechanical valve is used to replace a conventional camshaft driving valve and bring out the possibility of a fully variable timing control valve, and thus researches and scholars are interested in electromechanical valves, and many control strategies are derived for the electromechanical valve including valve timing control, valve lift control, soft landing, and soft releasing control, etc. However, an electromechanical valve mechanism with a general design still has the following issues:
(1) Extra Energy Loss: When an engine is operated, the valve is usually situated at a fully closed or opened position most of the time, and a general electromechanical valve requires a large power consumption to maintain the valve at the fully closed or opened position, and thus incurring unnecessary additional power consumption.
(2) Initial starting Current: In the design of a general electromechanical valve, the armature is situated at a central equilibrium position, and thus it is necessary to supply a large initial-current to bring the armature to a fully closed position before the engine is started, and such arrangement also causes unnecessary additional power consumption.
(3) Uneven Valve Wear: The valve is rotated when the conventional engine is operated, and thus the valve wear generally occurs evenly at the position where the valve is in contact with a cylinder, and the design of a common electromechanical valve generally comes with a square armature, and thus the armature cannot be rotated with the engine. In addition to the uneven valve wear, indirect impacts are exerted on the armature and the walls of the valve structure, resulting in damages or wearing of the electromechanical valve after a long use.
(4) Large Volume of Electromechanical Valve Coil: To provide a large magnetic force for pushing the valve, the electromechanical valve usually has a coil having an enormous volume.
(5) Excess Overall Volume: The volume of the electromechanical valve is too large, and thus the installation space above the engine cylinder head is limited, and the level of difficulty of the installation is increased.
(6) Demagnetism of Permanent Magnet: In a magnetic path of a general electromechanical valve, the lines of magnetic force produced by an electromagnet are passed through the lines of magnetic force (with opposite polarity) of the permanent magnet, and thus the magnetism of the permanent magnet is degraded gradually and the holding force of the valve will be reduced to a level of unable to open the valve.
It is an objective of the present invention to develop an electromechanical valve to overcome the shortcomings of the prior art.